'stomatal' originates from New Latin, specifically the word 'stomatalis', where the Greek root 'stoma' meant 'mouth' and the suffix '-al' meant 'relating to'.

'stomatal' changed from the New Latin word 'stomatalis' and eventually became the modern English word 'stomatal' through scientific/technical Latin usage in botanical contexts.

Initially, it meant 'relating to a mouth', but over time it evolved into its current meaning of 'relating to stomata (the tiny pores on plant surfaces)'.